There have been proposed dual IC cards capable of performing contact communication and contactless communication. For example, PTLs 1 to 3 each describe a dual IC card that includes an IC module having a communication function. The IC module is electromagnetically coupled (transformer-coupled) to an antenna provided to a card body to eliminate electrical contact between the IC module and the antenna.
With such a dual IC card having a contact communication function and a contactless communication function, communication modes can be used according to the user's applications. Thus, dual IC cards have been used for various applications. In such a dual IC card of recent years, an IC module having an antenna is joined to a card body by means of an insulative adhesive or the like, with another antenna being embedded in the card body. Thus, the dual IC card is ensured to be capable of receiving power supply and performing communication between the IC module and the card body by the electromagnetic coupling occurring between the antenna of the IC module and the antenna provided to the card body. By configuring the dual IC card in this way, unstable electrical connection between the IC module and the card body can be minimized. This is because, if the IC module and the card body are directly connected via a conductive connecting member, such as solder, the connecting member may be broken when the dual IC card is bent or the connecting member will be deteriorated with age.
As such a dual IC card in which an IC module and the card body are electrically connected by electromagnetic coupling, the IC cards described in PTLs 1 to 3 are known, for example.
In an IC module for a dual IC card, a terminal (contact terminal portion) for an interface that contacts an external contact machine is formed on a front surface, while a connecting coil for transformer-coupling (electromagnetic coupling) is formed on a back surface.
The card body includes an antenna substrate having a first surface of a sheet-like resin (substrate) which is provided with a coupling coil formed of a printed coil, and an antenna coil (main coil) both of which are ensured to be resin-sealed. The coupling coil is looped to surround an outer side of the IC chip in the IC module, when viewed in a thickness direction of the sheet-like resin.
The coupling coil of the card body is transformer-coupled with the connecting coil, and hence power supply can be received and communication can be performed between the antenna coil and an external contactless machine, such as a reader/writer.
As the applications of the dual IC cards, contact communication is used for applications that need reliability and security, such as large quantities of data exchange by credit-card transactions or communication for account settlement procedures. In contrast, contactless communication is used for applications where the communication data volume is small and the main communication is authentication, such as gate control for allowing someone to enter or leave a room.